Question 950678
S=son's age; F=father's age=S+30
F+5=3(S+5) Substitute for F.
(S+30)+5=3S+15 Subtract S from each side.
35=2S+15 Subtract 15 from each side.
20=2S Divide each side by 2.
10=S ANSWER 1: The son is 10 years old.
F=S+30=10+30=40 ANSWER 2: The father is 40 years old.
CHECK:
F+5=3(S+5)
40+5=3(10+5)
45=3(15)
45=45